As systems become more sophisticated, incorporation of increased amounts of data in controlling those systems is useful in maximizing the system performance. Thus, in automotive applications, data associated with the pressure of various media including air, gasoline or transmission oil may be used to optimize engine performance.
One practice in engine design directed toward increased fuel efficiencies is to mix engine exhaust with fresh air so as to preheat the incoming air. Obtaining the pressure of the resultant air/exhaust mixture, however, necessitates exposing a sensor element to a significantly more aggressive and hotter environment. Accordingly, contemporary pressure sensors require special protection of the electrical connections on the sensor.
One approach to protecting sensitive components of a sensor assembly from harsh environments is to deposit a gel over the sensor and electronics, thereby sealing the vulnerable electrical connections from the harsh media. Other sensors physically separate sensitive electronics from the harsh environment. In these sensors, one of a pair of coils, along with the sensitive electronics, is placed in a protected environment. A second coil an substrate, made of a material that is resistant to the harsh environment, is positioned in the harsh environment and data is passed between the coils.
While effective in isolating the sensitive components of the sensor from the harsh environment that is monitored by the sensor assembly, sensors incorporating additional materials introduce additional manufacturing steps. Moreover, the protective materials tend to break down over time and lose the ability to protect the sensor, thereby shortening the useful life of the sensor.
Additionally, as a monitored engine continues to be operated, the temperature of the exhaust varies. The change in temperature can affect the sensor assembly characteristics thereby exacerbating sensor system inaccuracies. Some of the temperature related inaccuracies may be mitigated by measuring the temperature and applying a temperature correction. As the number of sensors increases, however, costs associated with the system increase. Additionally, additional space is required for the additional component.
Accordingly, a sensor assembly which protects sensitive components from harsh environments without requiring protective materials on sensor components would be advantageous. A sensor assembly that provided temperature data along with pressure data would be further advantageous. A sensor assembly that used temperature data to optimize sensor system accuracy would be further advantageous.